DDDA
Secondary data from non-centralized data source
Danish Diabetes Database for Adults (DDDA) (Dansk Voksen Diabates Database, DVDD or NIP Diabetes) is a no longer active database from regionernes kliniske kvalitetsudviklingsprogram (RKKP). It was closed by 30 June 2022. It has now been replaced by Dansk Diabetes Database (DDD/DDiD), which has been active since 1 July 2022.
Extracts from the online DDDA documentation (downloaded 07 September 2023) about the population and variables can be downloaded here:
See also Jørgensen et al. (2016) for further information about the database.
Data
At KEA, we have data from DDDA in the period from May 2005 to June 2022 based on the n=11,382 individuals enrolled in DD2 per 13 April 2023. As the database is now closed, this is the final data set and we will not get any updates of it.
In the latest version of the DDDA data, around 80% (n=9,041) of the individuals in DD2 had at least one record in DDDA. The records in DDDA are uniquely defined based on the CPR-number and the variable status_dato which is the date that defines the data entry. There is a median of 3 (IQR 2-5) records per individual, 85% had at least one record prior to enrollment in DD2, and there was a median of -56 days (IQR -413-294) from the enrollment date to the nearest status_dato (negative value meaning that status_dato was before enrollment in DD2). The status_dato is not necessarily the date of the examination/results/visit. Many of the variables thus have an associated date variable that is different from status_dato.
When using data from DDDA, it is important to be aware of the missing data. Data can be missing for two reasons; because data is missing/not reported or because the individual is simply not registered in DDDA. Thus, when reporting data from DDDA, e.g., in a baseline table, remember to consider what “100%” should represent, as the interpretation of the result varies; is it x% of the entire study population or x% of the study population also registered in DDDA.
In addition, the selection and timing of data should be considered. Individuals registered in DDDA full the criteria for this database (see population documentation above) which might induce some selection bias. Individuals in DDDA might not be as newly diagnosed as individuals in DD2. The records in DDDA are defined based on status_dato which is “den dato, hvor der årligt, i relation til databasen, gøres status over hvornår personer senest har fået foretaget forskellige relevante undersøgelser.” The dates listed for each of the examinations might be long after (or before) enrollment in DD2, and for each scientific study question, it is thus crucial to consider in which time period data can be considered valid. An example could be to only include measurements in the period from 5 years prior to enrollment to 6 months after enrollment and then among these, include the one closest to the enrollment date as a “baseline” value. It all depends on the specific study.
A slightly changed version of the DDDA data has been uploaded to SDS and DST. The changes are mainly to comply with the SDS/DST regulations.
Variables from previous versions
In the current DDDA data, some variables from the database were not delivered. It was decided that the best suitable solution was to included these variable from older versions of data (and thus missing for some new individuals).
From the 2021 data:
shared_careandPlasmakreatinin_operatorFrom the 2018 data (also missing in the 2021 delivery):
diag_dato,HbA1c_kode,HDLcholesterol, andHDLcholesterol_undersoegelse_kod.